Estimation of magnetic susceptibility anisotropy of carbon nanotubes using magnetophotoluminescence

We have carried out a magnetophotoluminescence excitation spectroscopy study on micelle-suspended single-walled carbon nanotubes in high magnetic fields. By analyzing field-dependent spectral changes, we determined the degree of magnetic alignment of the observed semiconducting nanotubes at 45 T. This, together with an independently measured length distribution of the nanotubes, allowed us to estimate the magnitude of the magnetic susceptibility anisotropy chi(II) - chi(perpendicular to) to be similar to1.4 x 10(-5) emu/mol for 1-nm-diameter semiconducting nanotubes.